Low Head Dams

The infamous Dock Street Dam in Harrisburg, Pennsylvania. Due to the intense hydraulic behavior caused by the dam, there have been over 30 documented fatalities at the site since 1935. (DamFailures.org)

Many of the most dangerous dams are not the massive concrete structures people often first think of when thinking of dams. Many are low-head dams, also called run-of-the-river dams or "drowning machines". Low-head dams are dams characterized by their low height – usually with a one foot to fifteen foot drop off – that allows water to flow over the top of the dam. Below the surface, the water falling over the dam creates highly aerated, circulating currents that trap people and objects underwater against the face of the dam. These forces are a practically inescapable trap for even the strongest, life jacket clad swimmer or often boats and kayak too.

Low-head dams have a variety of purposes, including hydroelectric power generation, irrigation control, and historically, powering mills. While some dams no longer are needed to serve their original purposes, many others across the United States are still important components of our national water infrastructure.

Examples

Learn more about the dangers of low head dams like Dock Street Dam (DamFailures.org)

Trainings

On-Demand Webinar: Identifying Hazards and Improving Public Safety at Low Head Dams

Revision ID: 4203
Revision Date: 11/17/2022